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roomm Jannary LanoTlll - L - I may zuvo 40, criterion used for sites whe the conventional cover employs a composite barrier layer (Benson et al. 2001)." Monitoring the ET cover test section will be critical to evaluating the performance criteria of the alternative cover design. The primary criteria will be to monitor soil moisture. Soil moisture will be monitored using time domain reflectometers (TDB's) coupled with heat dissipation units (HDUs) to calculate infiltration/percolation rates at various depths within the test section. , In addition, the "Interim Final ET Cover" being placed over Module "I" shall also be monitored sufficiently for infiltration/percolation during the 5-year test period. The Discharger shall install additional TDRs and HDUs at depths of 1, 2, and 3 feet below the top elevation of the proposed "Interim Final ET Cover." The discharger shall place the additional instrument clusters at a rate of one per two acres for a total of 3 instrument clusters. It is recommended the monitoring system be wired with remote telemetry for quick and convenient access to the data. By 16 June 2006, the Discharger shall submit specifications and schematic drawings of the instrument clusters including a site figure showing the proposed instrument locations within Module "I". The test section is to be monitored for 5 years. During the 5 year test period, at least one above average wet season must be recorded. If one above average wet season is not recorded during the 5 year test period, the test will continue until an above average wet season is recorded. It is recommended data is downloaded monthly, and evaluated quarterly. Data shall be tabularized and submitted to the RWQCB in annual reports. The Discharger is also required to graph cumulative precipitation, soil water storage, percolation, surface runoff, and evapotranspiration over the duration of the test period. Discharger shall also monitor the vegetative root zone for growth and volumetric water content over the duration of the test period and present in graph form. Annual Reports shall be submitted 1 January 2007, 2008, 2009, 2010, and 2011 and include the data and Excel spreadsheets on compact disc or 3.5 inch floppy disc. If you have any questions please call me at (916) 464-4737. Todd A. Del Frate, PG Engineering Geologist San Joaquin River Watershed Land Disposal Unit cc: Robert McClellon, San Joaquin County Environmental Health Department, Stockton TADIW:\San Joaquin County\Letter_ET(3)0406